Machines, such as either self-propelled vehicles or vehicles that are pushed or pulled, often include wheels for facilitating travel across terrain. Such wheels often include a tire to protect a rim or hub of the wheel, to provide cushioning for improved comfort or protection of the operator, passengers or cargo, and to provide enhanced traction via a tread of the tire. Non-pneumatic tires are an example of such tires.
Non-pneumatic tires, such as solid tires or tires not retaining pressurized air or gas, may have advantages relative to pneumatic tires because they do not retain air or gas under pressure. However, non-pneumatic tires may suffer from a number of possible drawbacks. For example, non-pneumatic tires may be relatively heavy and may not have a sufficient ability to provide a desired level of cushioning. For example, some non-pneumatic tires may provide little, if any, cushioning, potentially resulting in discomfort for vehicle occupants and/or damage to cargo. In addition, some non-pneumatic tires may not be able to maintain a desired level of cushioning when the load changes on the tire. In particular, if the structure of the non-pneumatic tire provides the desired level of cushioning for a given load, it may not be able to continue to provide the desired level of cushioning if the load is changed. For example, if the load is increased, the structure of the non-pneumatic tire may collapse, resulting in a loss of the desired level of cushioning or potential damage to the tire. If the load is decreased, the level of cushioning may also decrease, resulting in an undesirable reduction in comfort and/or protection. In addition, conventional non-pneumatic tires that provide adequate cushioning may not be able to maintain the desired vehicle ride height when loaded due to collapse of the tire under the load. Thus, it may be desirable to provide a non-pneumatic tire that provides a desired combination of support and cushioning across changing loads.
An example of a non-pneumatic tire is disclosed in U.S. Patent Application Publication No. US 2013/0340902 A1 to Kemeny (“the '902 publication”). In particular, the '902 publication discloses shock-absorbers used as wheel-spokes between a wheel-hub and a rigid rim. According to the '902 publication, the compliance of the shock-absorbers is commensurate with that of a comparable inflated tire, but optimized passively or actively circumferentially, vertically, and laterally. The gas or liquid of the shock-absorbers may be interconnected and cooled, and soft and hard driving may be controlled manually or by a computer on the fly.
Although the non-pneumatic tire disclosed in the '902 publication may purportedly provide controllable levels of shock-absorption, it may suffer from a number of drawbacks. For example, the tire disclosed in the '902 publication is very complex and thus may be prohibitively expensive and suffer from unreliability, particularly when used in harsh environments or under demanding operating conditions. Further, the tire may be relatively difficult or expensive to manufacture on a large scale due to the mechanical interconnections between parts.
The non-pneumatic tires disclosed herein may be directed to mitigating or overcoming one or more of the possible drawbacks set forth above.